As disclosed in PTD 1 to PTD 5, a power transfer system is known in which a power transmission device and a power reception device that receive and transmit electric power in a contactless manner are used. PTD 6 relates to a contactless battery charger for conveying electric power by an electromagnetic induction effect to charge a battery stored in a battery-driven device, such as a cellular phone, a smartphone or a tablet, in a contactless manner or wirelessly. A coil and a circuit board are stored in an exterior case. PTD 7 discloses a storage case in which a coil and a capacitor are stored, wherein a mounting surface is made of metal and a power transfer surface and its surroundings are made of resin.